1. Field of the Invention
The present invention relates to a semiconductor device and a method of manufacturing the semiconductor device, a circuit board, and an electronic instrument.
2. Description of Related Art
Bare chip mounting is ideal when continuing to pursue the miniaturization of a semiconductor device. However, because providing a guarantee of its quality and handling bare chips are difficult, the miniaturization has been achieved by fabricating the semiconductor device into a packaged form. In recent years, a ball grid array (BGA) type package has been applied to the packaged form in response to the need for high pin terminal. The BGA type package is classified into several kinds according to the base materials of the substrate. A flexible tape type BGA package using a flexible base material as the base material for the substrate has been proposed to respond to the need for mounting fine pitch pad semiconductor elements and to satisfy the demand for increasing the manufacturing efficiency by fabricating the semiconductor devices continuously by using tape-shaped packages. The BGA package is made so that bumps, i.e., external terminals, are arranged on a flexible substrate like an area array to allow surface mounting.
The heat generated by a semiconductor device has increased in connection with small sizing and speeding up. For cooling, it has been common to couple a heat spreader (radiating plate) to a semiconductor chip.
A closed area is formed by the heat spreader and a flexible tape in the BGA package. Because the air in this closed area cannot be exhausted, heating in the subsequent reflow process sometimes caused the internal air to expand, resulting in the generation of cracks.
Accordingly, a passage for exhausting air has been generally formed by providing a hole or projection in the heat spreader, which required an additional step in a process for fabricating the heat spreader. Since the heat spreader is made of a metal with a high heat conductivity, it is difficult to work the heat spreader. Therefore, the heat spreader may be distorted in the course of working. Note that these problems can occur when providing various supporters as well as the heat spreader.
The present invention has been achieved to solve the problems described above. Accordingly, an object of the present invention is to provide a semiconductor device in which generation of cracks due to heating in a reflow process can be avoided even if a heat spreader is provided, a method of manufacturing such a semiconductor device, a circuit board, and an electronic instrument.
According to a first aspect of the present invention, there is provided a semiconductor device comprising:
an insulating film on which wires are formed and in which a through-hole is formed;
a semiconductor element connected to the wires;
a resin provided in a connection portion between the semiconductor element and the insulating film; and
a supporter adhered to the semiconductor element, the insulating film and the supporter defining at least a part of a space, and the space being opened to the through-hole for ventilation from outside.
In accordance with the present invention, a through-hole is formed in the insulating film, at a position corresponding to the space partitioned by members including the insulating film and the supporter. Accordingly, even if the air enclosed in this space is heated in the reflow process and caused to expand, the air can be exhausted via the through-hole in the insulating film. Because it is easier to form a through-hole in the insulating film than in the supporter, providing a through-hole in the insulating film does not unduly increase manufacturing steps or lowers the production yield.
The resin may be provided to avoid the through-hole.
The supporter may accelerate the diffusion of heat from the semiconductor element.
The semiconductor device may further comprise a plate with plane maintenance strength higher than the plane maintenance strength of the insulating film, adhered to a position in the insulating film avoiding the semiconductor element. Contours of the insulating film and the supporter may be formed to be larger than the contour of the semiconductor element. The space may be formed in an area defined by opposite sides of the insulating film and the supporter, outer peripheral end sides of the semiconductor element, and end sides of the plate on a side of the semiconductor element.
According to this configuration, a space is formed in the circumference of the semiconductor element, and a through-hole is formed in the insulating film at the position corresponding to the space. Moreover, a plate is adhered to the insulating film, so that the planarity of the insulating film can be maintained.
The semiconductor device may further comprise external electrodes formed on a first side of the insulating film opposite to a second side of the insulating film on which the wires are formed, the external electrodes being connected to the wires through the insulating film at positions outside of the semiconductor element. The semiconductor element may be adhered to the wires of the insulating film with an active surface of the semiconductor element facing the wires. The plate may be adhered to the second side of the insulating film at a position outside of the semiconductor element. The supporter may be adhered to the semiconductor element on a side opposite to the active surface and also to the plate on a side opposite to a side to which the insulating film is adhered.
The contours of the insulating film and the supporter may be formed to be larger than the contour of the semiconductor element. The supporter may have plane maintenance strength higher than the plane maintenance strength of the insulating film and may be adhered to the insulating film and the semiconductor element. The space may be formed in an area defined by opposite sides of the insulating film and the supporter, outer peripheral end sides of the semiconductor element, and end sides of the supporter on a side of the semiconductor element.
A rectangular device hole may be formed in the insulating film, the wires may be formed on the insulating film avoiding the vicinity of corners of the device hole, and the through-hole may be formed in the insulating film in the vicinity of corners of the device hole.
According to this configuration, since it is hard to form wires on the insulating film in the vicinity of corners of a device hole, the wires are formed in areas avoiding the vicinity of the corners, so that the through-hole can be formed in the vicinity of the corners to allow air to be exhausted.
According to a second aspect of the present invention, there is provided a semiconductor device comprising:
an insulating film on which wire are formed;
a semiconductor element connected to the wires and mounted on the insulating film;
a resin provided in a connection portion between the semiconductor element and the insulating film; and
a supporter adhered to the semiconductor element;
the insulating film and the supporter forming at least a part of a space; and
the insulating film having a portion allowing ventilation into the space from outside.
According to a third aspect of the present invention, there is provided a method of making a semiconductor device comprising the steps of:
preparing a film carrier tape having wires, a device hole, and a through-hole other than the device hole;
connecting a semiconductor element to the wires;
providing a resin in a connection portion between the semiconductor element and the film carrier tape;
stamping out from the film carrier tape an insulating film larger in size than the semiconductor element; and
adhering a supporter larger in size than the semiconductor element to the semiconductor element, allowing a space to be defined at a position corresponding to the through-hole, at least a part of the space being defined by the insulating film and the supporter.
According to this method, a semiconductor device with a through-hole ventilating air from a space can be manufactured.
In this method, the resin may be provided to avoid the through-hole.
This method may further comprise a step of adhering a plate to the film carrier tape on a side on which the wires are formed and at a position avoiding the semiconductor element, the plate having plane maintenance strength higher than the plane maintenance strength of the insulating film.
According to a fourth aspect of the present invention, there is provided a circuit board on which the aforementioned semiconductor device is mounted.
According to a fifth aspect of the present invention, there is provided an electronic instrument which has the circuit board described above.